Novel high-efficiency composite viscosity reducer for super heavy oil

Abstract

The invention relates to an oil-soluble and water-soluble composite temperature-resistant and salt-resistant viscosity reducer for super heavy oil in the field of petroleum exploitation. The composite viscosity reducer contains oil-soluble viscosity reducer A and water-soluble viscosity reducer B, and mass ratio of the oil-soluble viscosity reducer A to water-soluble viscosity reducer B is 1:(4-9). The viscosity reducer provided by the invention has the following advantages: the viscosity reducer has temperature resistance (up to 140 DEG C), salt resistance (up to 22*10<4>mg/L), and combines the advantages of both oil-soluble viscosity reducers and water-soluble viscosity reducers; the viscosity reducing effect is obviously superior to the effect of single use of oil-soluble viscosity reducer and water-soluble viscosity reducer; the application range is wide; the viscosity of the oil phase can be reduce after demulsification; and demulsification is not affected and water quality is not influenced. The viscosity reducer provided by the invention can greatly saves consumption of thin oil and exploitation cost when being used for well casing viscosity reduction; and can effectively improve exploitation and delivery performance of heavy oil/super heavy crude oil and greatly increase well yield when being used for heavy oil viscosity reduction.

Description

technical field [0001] The invention relates to a novel high-efficiency composite viscosity reducer used in the field of petroleum exploitation for viscosity reduction of ultra-heavy oil, and the international patent classification number is C10M or C10G. Background technique [0002] In the process of petroleum development, the exploitation of heavy oil has generally been paid attention to. Shallow heavy oil reservoirs have low temperature, and the heavy oil has poor fluidity under reservoir conditions, and steam flooding is usually used to exploit them; deep wells / ultra-deep wells have relatively high reservoir temperatures, and can flow under reservoir conditions. With the lifting of the wellbore, the viscosity of the crude oil gradually increases, and even becomes unable to flow, which seriously affects the production of heavy oil. The wellbore viscosity reduction methods for heavy oil wells proposed at home and abroad mainly include thermal methods (including heating c...

AI Technical Summary

Problems solved by technology

At present, oil-soluble viscosity reducer and water-soluble heavy oil viscosity reducer are in the experimental stage, and their main problems are: (1) oil-soluble viscosity reducer is suitable for low water content (<10%) heavy oil viscosity reduction, and the viscosity reduction effect is poor

Two reasons cause the current oil-soluble viscosity reducer to have poor viscosity reduction effect

(2) Water-soluble viscosity reduction technology is suitable for low viscosity (viscosity 4 mPa·s), high water content (>30%) and low salinity heavy oil viscosity reduction, and the difficulty of demulsification caused by the use of water-soluble viscosity reduction technology

Most of them are the composite type of crude oil emulsification viscosity reducer and the compound use of various emulsification viscosity reducers. The patent is mainly to compound different types of emulsifying surfactants with alkali, which is mainly used for oil well schedule maintenance. Its disadvantage is: due to the addition of alkali in its formula, if this invention formula is used, the alkali in the formula and the acidity in crude oil The production of soaps by the action of components will make it difficult to break the emulsion of the produced fluid, and the viscosity of crude oil cannot be reduced after oil-water separation

[0007] The cost of using oil-soluble viscosity reducer alone is high; it is difficult to emulsify extra-heavy oil and super-heavy oil with water-soluble viscosity reducer alone. Compound heavy oil viscosity reducer is the key to the application of heavy oil chemical viscosity reduction technology in production

[0008] In view of the increasing shortage of thin oil resources and the limitations of existing oil-soluble and water-soluble viscosity reducers, the present invention proposes a new type of viscosity reducer formed under certain conditions based on the above background technology. The composite viscosity reducer overcomes the defects of using oil-soluble viscosity reducer and water-soluble viscosity reducer alone, and brings together the advantages of both. High-efficiency composite heavy oil viscosity reducer, which can reduce the viscosity of the oil phase after viscosity reduction, has no effect on demulsification, and has a good prospect for popularization and application

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